chore: setup systemtests in CI (#23886)

Co-authored-by: Tyler <48813565+technicallyty@users.noreply.github.com>

systemtests/system.go

@@ -569,7 +569,7 @@ func (s *SystemUnderTest) ForEachNodeExecAndWait(t *testing.T, cmds ...[]string)
 func MustRunShellCmd(t *testing.T, cmd string, args ...string) string {
 	t.Helper()
 	out, err := RunShellCmd(cmd, args...)
-	require.NoError(t, err)
+	require.NoError(t, err, out)
 	return out
 }
 
@@ -579,7 +579,7 @@ func RunShellCmd(cmd string, args ...string) (string, error) {
 		args...,
 	)
 	c.Dir = WorkDir
-	out, err := c.Output()
+	out, err := c.CombinedOutput()
 	if err != nil {
 		return string(out), fmt.Errorf("run `%s %s`: out: %s: %w", cmd, strings.Join(args, " "), string(out), err)
 	}